The tricolored bat, formerly known as the eastern pipistrelle, is one of the smallest bats in North America. Its name may seem misleading, since these bats appear to be a solid yellowish brown, but each individual hair is “tricolored” with a brown tip, a yellow middle and a dark base. The tricolored bat ranges across most of eastern North America and the midwestern United States. Tricolored bats are a hibernating species and have the longest hibernation period of any bat species in their range. When not hunkering down for the winter, they may be found in a wide variety of habitats to roost and forage.  


White-nose syndrome — a devastating disease that is wiping out North American bat species — is the greatest and most immediate threat to the survival of tricolored bats. Infected populations have experienced 75 percent to 100 percent mortality rates as the epidemic continues to spread across the country. These bats' long hibernation periods and selection for the very back of caves, and other shelters where environmental conditions favor disease transmission, may make this species exceptionally susceptible.


Tricolored bats are also threatened by human disturbance at hibernation and roost sites, wind energy, habitat loss, pesticides and climate change. The species' low reproductive rate constrains its ability to recover quickly from the dramatic population decline associated with WNS and these other factors. Because of these ongoing threats, which often act in synergy to exacerbate one another, the Center petitioned the U.S. Fish and Wildlife Service to have the tricolored bat listed as a threatened or endangered species under the Endangered Species Act.

Photo of tricolored bat by Phillip Jordan/USFS